The invention relates to a dispensing head for a dispenser which is pressurized by squeezing the sides of the container. More particularly, the invention is directed to a dispensing head in which air and liquid are mixed to produce a fine spray, and in which there is a venting arrangement with an anti-leak feature, and a flow controller for sealing off the dispensed liquid from the atmosphere when the dispenser is not in use.
There are several different techniques for dispensing a fluid substance in a fine mist. One technique is to provide a resilient dispensing bottle with an outlet orifice such that as the bottle is squeezed by a user, pressure builds up within the container. The pressure in the container forces any liquid within the container out a dispensing orifice, which can be structured to produce a fine mist of liquid. Often, however, it is difficult to arrive at a particularly fine mist in such a dispenser solely through the use of a shaped orifice. Furthermore, the conventional means for providing an outlet valve-a ball valve-is generally expensive to manufacture, thus increasing the cost of the dispenser to the end user.
A technique used to eliminate some of the above disadvantages is disclosed in U.S. patent application Ser. No. 745,538, which is incorporated by reference. In this invention, a squeeze bottle has a liquid flow path and an air flow path. When the bottle is squeezed, liquid is transmitted through the liquid flow path and pressurized air through the air flow path. These two flows meet in a mixing chamber which is located adjacent an outlet orifice. The air and liquid mix to form a fine spray. The disadvantage of this arrangement is that it requires the use of a relatively expensive ball valve for the liquid outlet, and liquid will leak out of the dispenser when the bottle is inverted, because the air path is completely open to fluid flow. Furthermore, in this arrangement, the outlet orifice and the air vent path allow air to be in continuous contact with the liquid to be dispensed. This can result in drying of the liquid substance--an disadvantageous result which can clog the outlet orifice and prevent proper spraying.